FIGS. 3 through 5 illustrate a socket comprising a box-shaped housing 1, and a plurality of terminal pieces 5. Each of the terminal pieces 5 comprises a socket portion 7 made of elastic and electroconductive material and adapted to receive a lead pin of an electronic component such as IC's and small relays not shown in the drawings, and a lead portion 6 extending integrally therefrom. Each of the socket portions 7 is securely received in an associated one of a plurality of cavities 2 provided in the housing 1, and the lead portions 6 are each passed through an associated one of a plurality of through holes 4 extending across the bottom wall of the housing 1 and project from the bottom surface of the housing 1. In this case, the lead portions 6 consist of a generally planar tongue piece. When this socket is mounted on a circuit board 10, each of the lead portions 6 is passed through a mounting hole 11 of the printed circuit board 10, and is soldered to an electroconductive pattern 12 formed on the external surface of the printed circuit board 10.
However, according to this socket, flux which is used for soldering its lead portions 6 tends to get into the gaps between the through holes 4 and the lead portions 6 through the gaps between the mounting holes 11 and the lead portions 6 thereby causing flux to be deposited on the surface of the socket portion 7 of each of the terminal pieces 5, and bad contact could occur.
In particular, when a large current capacity is involved, the width of each lead portion 6 becomes accordingly large, and the chance of flux intrusion and resulting bad contact increases due to the increase in the diameter of each of the mounting holes 11 of the printed circuit board 10 and the gaps between the through holes 11 and the lead portions 6.
To eliminate this problem, it may be possible to bend each lead portion 6 into a C-shaped cross section to thereby reduce the diameter of the through holes 4 and the mounting holes 11 as illustrated in FIG. 6 through 8 in which like parts are denoted with like numerals. In this way, it is possible to reduce the gaps between the mounting holes 11 of the printed circuit board 10 and the lead portions 6. However, flux can still pass through the groove 6a of each of the terminal pieces 6, and get into the socket portion 7.
FIGS. 9 and 9 illustrates a structure which utilizes a sealant 8 to close the gap between the lead portion 6 of each of the terminal pieces 5 and the associated through hole 4 of the housing 1. The bottom surface of the housing 1 is provided with a depression 1a, and the sealant 8 is filled into this depression 1a. The sealant 8 can thus effectively close the gaps between the lead portions 6 and the through holes 4.
However, according to this structure, the sealant 8 tends to cling to the surface of each of the lead portions 6 and travel along it when filling the sealant 8 into the depression 1a, and this not only could cause bad contact at the socket portions 7 but also could prevent close contact between the housing 1 and the printed circuit board 10 because a part of the sealant 8 which has solidified around the base end of each of the lead portions 6 could abut the surface of the printed circuit board 10, thereby causing fluctuations in the mounting height of the housing 1 relative to the printed circuit board 10.